STOCKTON - The city's signature event, a waterfront party devoted to a green vegetable, attracts as many as 100,000 Northern California visitors and brings out the best in Stockton.

The 28th annual Stockton Asparagus Festival is this weekend. Its footprint encompasses many of downtown's landmarks - City Hall, Weber Point Events Center, the Stockton Memorial Civic Auditorium and the Cesar Chavez Central Library.

This is the festival's 10th year in the city's core.

For executive director Kate Post, the three-day event represents a logistical challenge made possible by an army of altruistic residents. More than 5,500 volunteers representing 129 nonprofit agencies across San Joaquin County lend a hand.

It also represents something more.

"The volunteer spirit is amazing," Post said. "There's a need to be a part of the whole. There's a primitive need for us to gather and to celebrate. This is a real important part of the festival - for our volunteers to feel important and needed."

For more than a week leading up to the festival, some of those volunteers have blocked off streets, erected huge tents and canopies, set up vendor booths, converted the Civic, descended on Dr. Martin Luther King Jr. Plaza and beautified various intersections along El Dorado and Center streets.

More local benevolence begins Friday, the festival's first day, and runs through Sunday. There is intensity throughout the event, but it's hard to find more action than inside Asparagus Alley, where last year hundreds of selfless residents served up 62,950 dishes.

"If we didn't have that kind of core of volunteers, we wouldn't have a festival," Post said.

Last year, volunteers devoted 33,218 hours to making the Asparagus Festival a success. The 2012 payoff was the second-largest crowd in its history, 104,158, and $314,972 raised for charity.

One difference festivalgoers will find this year is a return to the past. Asparaberry Shortcake, first served in the 1980s and '90s at Oak Grove Regional Park, is back. Only the spear tips are used, giving the dessert a nutty consistency.

The weather this weekend is expected to be ideal, with highs ranging from the upper 70s to the low 80s.

When the gates open at 10 a.m. Friday, the festival is quieter and feels more like a small community get-together - at least for the first few hours.

Adding color this year will be the Red Hat Society, a fast-growing social organization for women. Post expects more than 300 red-hat wearers to attend Friday, including three tour buses bringing members from outside the area. A Red Hat Society group will perform at 12:15 p.m. at Dean De Carli Waterfront Plaza.

The festival has been recognized frequently by outsiders since its first year in April 1986. It still carries the label "Best of the West Food Fest," awarded by Sunset magazine in 2000.

But the reputation Post likes best is the one that year after year adds up to contributions for local nonprofit organizations. Since its first year, the Asparagus Festival has raised an estimated $5.8 million.

"This is one of the largest charitable festivals in the state, if not the country," Post said.